The present invention relates to collapsible boats, such as those formed by panels hinged together. More particularly, the invention relates to a method for bracing such boats when in an erected configuration to provide stiffness and rigidity.
It is known to provide collapsible boat hulls, comprising a pair of hingedly interconnected bottom panels and a pair of side panels hinged to the bottom panels. Such boats can be collapsed and folded along the hinging edges of the panels into a substantially flat configuration for ease of transport and storage, and then erected into a suitable hull shape for use on water. Typically, collapsible boat hulls are also provided with a stern member functioning as a transom, a bow member, and seats which are mounted onto the boat hull when the boat hull is in an erected configuration. It is important that the junction between the boat hull and the bow member, and the boat hull and the stern member, are leak-proof. Provision is generally also made to mount an outboard motor on the stern member. Some collapsible boat hulls are provided with rigid stern members, while others are provided with diaphragms that can accommodate rigid panels, which rigidify and stabilise the diaphragm when an outboard motor is mounted thereon. The stress exerted on the boat hull by the outboard motor mounted on the stern members, however, has meant that it has not generally been possible to use outboard motors whose power exceeds about 4 horsepower.
In a traditional boat design, rigidity and stiffness including torsional stiffness are largely achieved by the provision of ribs extending laterally across the hull of the boat. These provide lateral support, complementing the longitudinal support provided by stringers, the hull panels and strakes in the hull and thus strengthening the hull in two dimensions. As a result, stiffness and rigidity of the hull is established, particularly in response to torsional forces.
In a collapsible boat, it has not proved possible to include ribs in the same way, although attempts have been made. As a result, many collapsible boats have a limited capacity to resist twisting as a result of torsional forces.
One method employed to provide bracing in collapsible boats is to use seats of the boat for this purpose. Such bracing is largely ineffectual, as the seat is spaced from the boat hull, and has no direct connection to panels at the base of the boat or to the transom.
A degree of torsional stiffness can be gained near a boat's transom by coupling of the transom to each of the panels. Typically, the transom of a collapsible boat is a removable member. A suitable coupling arrangement can be complex, and make assembly of the boat more difficult.
The present invention seeks to provide a means for bracing a collapsible boat which overcomes, at least in part, some of the above mentioned disadvantages.